Man walking past invisible bodies. Photo: Getty Images
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Scientists suggest invisibility as a cure for anxiety

Neuroscientists have made the surprise discovery that the sensation of invisibly reduces responses to anxiety.

Have you ever felt fear and anxiety from standing in front of a large audience and giving a speech? Or how about having to get up in class and talk to other students? While it's normal in situations like these to wish for the ground to swallow you up, some scientists have suggested a slightly different remedy for anxiety - invisibility.

Invisibility has long featured in myths and fiction, but several advances in material sciences have demonstrated that the cloaking of large (living) objects - just like how the invisibility cloak works in Harry Potter - is becoming a realistic prospect. In the field of material sciences, the general concept of invisibility cloaking is actually fairly simple.

Theoretically, all that's needed is a material that guides visible light (or another wave, like EM waves or heat fluxaround an object, and anything within the gap it leaves will be rendered "invisible" to someone standing at the light source:

Light moves around the object (or person) as though it isn't there. Image: Trevor Johnston/trevorjohnston.com

In practice, this is hard to achieve, as most naturally occurring materials reflect light, cast shadows and produce a reflection. However, hi-tech and exotic materials called "metamaterials" have made light bending possible. (Although latest research suggest that ordinary lenses can do just the trick!)

H G Wells, a man ahead of his time, wrote the The Invisible Man in 1897. The novel is about a protagonist who invents a method to change the human body’s refractory index to that of the air, rendering it invisible. (The twist comes when he performs the method on himself and can’t reverse it - but that’s beside the point.) The refractive index is the ratio between how light passes through a vacuum, and how it passes through any other medium; it’s the reason a spoon will look bent when placed in a glass of water. If water has a negative refractive index, the spoon would look as though as was bending back on itself instead.

In a recent paper in Scientific Reports, graduate students Arvid Guterstam and Zakaryah Abdulkarim and their advisor Henrik Ehrsson, a neuroscience professor at the Karolinska Institutet in Stockholm, said they believe invisibility cloaking of the human body is a thing of the future, and believe it’s high time we delve into what it feels like to be invisible.

To do this, Guterstam, Abdulkarim, and Ehrsson used virtual reality. In one of their experiments, 23 people were provided with a set of head-mounted displays (HMD), and were asked to look at their feet. The experimenter - Abdulkarim - stroked their arms, legs, and torso with a paintbrush with one hand, and at the same time, made identical motions with a second paintbrush with the other hand, on an invisible body or a mannequin. A pair of downward-facing cameras that were either mounted on a tripod or on the head of a mannequin sent a real-time video feed to the participants HMDs, giving them the sensation of being invisible, or making a body swap with a mannequin:

Study co-author Zakaryah Abdulkarim (middle) creates the invisible body illusion on a participant (left) wearing a set of head-mounted displays connected to a pair of cameras. Photo: Staffan Larsson

Here's the surprise: after finishing with the paintbrush, each participant slowly lifted their gaze through their HMDs to find that they were being watched by a scornful-looking audience (consisting of 11 scientists instructed to stare at the participant). Quite creepy, and perhaps enough to through most people off - however, on a 100-point scale, participants reported their stress level as about 25 per cent lower, on average, when in a state of invisibility, and about a third less than in the mannequin version. The state of invisibility also lowered heart rates by a few beats per minute, suggesting that stress is intertwined with physiology.

The researchers write: “Our results demonstrate that healthy individuals can experience the illusion of owning an invisible full body." They suggest their results could spur on better a design for virtual-reality based therapies for social anxiety, and may also help give neuroscientists gain new insight into phantom limb illusions.

Tosin Thompson writes about science and was the New Statesman's 2015 Wellcome Trust Scholar. 

KARIM SAHIB/AFP/Getty Images
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Apple-cervix ears and spinach-vein hearts: Will humans soon be “biohacked”?

Leafy greens could save your life – and not just if you eat them.

You are what you eat, and now bioengineers are repurposing culinary staples as “ghost bodies” – scaffolding on which human tissues can be grown. Nicknamed “biohacking”, this manipulation of vegetation has potentially meaty consequences for both regenerative medicine and cosmetic body modification.

A recent study, published in Biomaterials journal, details the innovative use of spinach leaves as vascular scaffolds. The branching network of plant vasculature is similar to our human system for transporting blood, and now this resemblance has been put to likely life-saving use. Prior to this, there have been no ways of reproducing the smallest veins in the human body, which are less than 10 micrometres in diameter.

The team of researchers responsible for desecrating Popeye’s favourite food is led by bioengineering professor Glenn Gaudette and PhD student Joshua Gershlak at the Worcester Polytechnic Institute (WPI). They were discussing the dearth of organ donors over lunch when they were inspired to use their lunch to help solve the problem.

In 2015 the NHS released figures showing that in the last decade over 6000 people, including 270 children, had died while waiting for an organ transplant. Hearts, in particular, are in short supply as it is so far impossible to perfectly recreate a human heart. After a heart attack, often there is a portion of tissue that no longer beats, and so cannot push blood around the body. A major obstacle to resolving this is the inability to engineer dense heart muscle, peppered with enough capillaries. There must be adequate flow of oxygenated blood to every cell in order to avoid tissue death.

However, the scientists had an ingenious thought – each thin, flat spinach leaf already came equipped with its own microscopic system of channels. If these leaves were stacked together, the resulting hunk of human muscle would be dense and veiny. Cautiously, the team lined the cellulose matrix with cardiac muscle cells and monitored their progress. After five days they were amazed to note that the cells had begun to contract – like a beating heart. Microbeads, roughly the same size as blood cells, were pumped through the veins successfully.

Although the leafy engineering was a success, scientists are currently unaware of how to proceed with grafting their artificial channels into a real vasculatory system, not least because of the potential for rejection. Additionally, there is the worry that the detergents used to strip the rigid protein matrix from the rest of the leaf (in order for human endothelial cells to be seeded onto this “cellulose scaffolding”) may ruin the viability of the cells. Luckily, cellulose is known to be “biocompatible”, meaning your body is unlikely to reject it if it is properly buried under your skin.

Elsa Sotiriadis, Programme Director at RebelBio & SOSventures, told me: “cellulose is a promising, widely abundant scaffolding material, as it is renewable, inexpensive and biodegradable”, adding that “once major hurdles - like heat-induced decomposition and undesirable consistency at high concentrations - are overcome, it could rapidly transform 3D-bioprinting”. 

This is only the most recent instance of “bio-hacking”, the attempt to fuse plant and human biology. Last year scientists at the Pelling Laboratory for Biophysical Manipulation at the University of Ottawa used the same “scrubbing” process to separate the cellulose from a slice of Macintosh red apple and repopulate it with “HeLa” cervix cells. The human ear made from a garden variety piece of fruit and some cervix was intended as a powerful artistic statement, playing on the 1997 story of the human ear successfully grafted onto the back of a live mouse. In contrast to the WPI researchers, whose focus is on advancing regenerative medicine – the idea that artificial body parts may replace malfunctioning organic ones – Andrew Pelling, head of the Pelling Laboratory, is more interested in possible cosmetic applications and the idea of biohacking as simply an extension of existing methods of modification such as tattooing.

Speaking to WIRED, Pelling said: “If you need an implant - an ear, a nose - why should that aesthetic be dictated by the company that's created it? Why shouldn't you control the appearance, by doing it yourself or commissioning someone to make an organ?

The public health agency in Canada, which is unusually open to Pelling’s “augmented biology”, has supported his company selling modified body parts. Most significantly, the resources needed for this kind of biohacking – primarily physical, rather than pharmacological or genetic – are abundant and cheap. There are countless different forms of plant life to bend to our body ideals – parsley, wormwood, and peanut hairy roots have already been trialled, and the WPI team are already considering the similarities between broccoli and human lungs. As Pelling demonstrated by obtaining his equipment via dumpster-diving and then open-sourcing the instructions on how to assemble everything correctly, the hardware and recipes are also freely available.

Biohacking is gaining popularity among bioengineers, especially because of the possibility for even wackier uses. In his interview with WIRED, Pelling was excited about the possibility of using plants to make us sexier, wondering whether we could “build an erogenous interaction using materials that have textures you find pleasing [to change how our skin feels]? We're looking at asparagus, fennel, mushroom...” If he has his way, one day soon the saying “you are what you eat” could have an entirely different meaning.

Anjuli R. K. Shere is a 2016/17 Wellcome Scholar and science intern at the New Statesman

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